RE: SPI Slave receive buffer gets garbage values

Edvin — Mon, 20 Apr 2020 12:50:01 GMT

Hello,

I think the first thing you should check is that you are using the correct SPI mode.

NRF_DRV_SPIS_DEFAULT_CONFIG sets the spis_config.mode = NRF_SPIS_MODE_0. I don't know what mode your SPIM uses, but the quickest way to check is to try all the modes:
NRF_SPIS_MODE_0
NRF_SPIS_MODE_1
NRF_SPIS_MODE_2
NRF_SPIS_MODE_3

Just set:

spis_config.mode = NRF_SPIS_MODE_1

after you configure the pins to test mode 1.

If that doesn't do the trick, then check that you have wired the connection correctly. Are you sure that you set MOSI -> MOSI and MISO -> MISO (and not the opposite)?

Another thing to check is the pull of the pins. What way does your SPIM drive the pin? Check:

spis_config.csn_pullup = NRFX_SPIS_DEFAULT_CSN_PULLUP,

My hunch is on the mode, but let me know if this doesn't work.

By the way, what is the frequency that your SPIM use?

Best regards,

Edvin

RE: SPI Slave receive buffer gets garbage values

tp2k20 — Fri, 17 Apr 2020 21:44:13 GMT

In case the figure above is unclear, please see the attached figure.